It is known that the shutters making up the lift doors are typically composed of rolled sections or bearing frames for various types of covering; these panels are coupled in the upper portion to shaped plates whereon the sliding carriages or part of them are fastened. These shaped plates are traditionally bound to the panels by means of bonded joints or, in any case, using permanent fastening means that entail troublesome and, hence, expensive operations.
The very shutter panels require the presence, on the opposite lower front, of further plates forming the bearing of the traditional shoes that slide in the sill grooves or races.
Even in this case, the mentioned shoe bearing plates are generally fastened to the panel by bonded joints or equivalent means, similarly to the plates that are meant to fasten the carriage.
The known panels, furthermore, are sometimes equipped with stiffening members in the form of metal rolled sections of various shapes and sizes, which also require troublesome assembling operations, that is for a stable connection to the mentioned panels.
All considered, the manufacture of each panel according to the known art involves a number of operations, part of which are manual, which are very expensive and demand long manufacturing time.